1. Field of the Invention
The present invention relates generally to exercise devices, and more specifically to a hand-held gyroscopic exercise ball.
2. Description of the Related Art
Gyroscopic exercise balls are hand-held devices used in therapy and strengthening exercises, primarily to exercise the hand and wrist. Such gyroscopic exercise balls are commercially available. Two such devices currently available are the DYNABEE and the POWERBALL available from Play Trend Exclusive Worldwide and Nano-second Technology Co., Ltd., respectively. U.S. Pat. No. 3,726,146 to Archie Mishler describes a gyroscopic exercise ball including a rotor which rotates about its spin axis and about a second axis at right angles to the spin axis, which rotor increases in speed by applying a torque about a third axis. This phenomenon is commonly referred to as precession.
Typically, a gyroscopic exercise ball includes a rotor centrally disposed on a shaft within a spherical housing. The housing almost fully encases the rotor except for a small circular opening through which a portion of the rotor extends in order to give the rotor an initial spin about its spin axis. The ends of the shaft are mounted in notches of a lightweight ring, or gimbal, which is disposed in a groove of the housing which circumferentially surrounds the rotor. The groove is wider than the diameter of the ends of the shaft and also allows the lightweight ring to spin therein. In response to an external torque, applied by the wrist, one end of the shaft rolls around the top edge of the groove while the other end rolls around the bottom edge as the lightweight ring rotates, thereby causing the rotor to speed up. As a general rule, the higher the applied torque, the faster the rotor will spin.
Recently, gyroscopic exercise balls have been provided with mechanisms for calculating the speed and/or number of revolutions of the rotor. One such device, described in U.S. Pat. Nos. 5,150,625 and 5,353,655 to Frederick Mishler, includes an optical device coupled with a counter for determining the speed of the rotor. The gyroscopic exercise ball also includes Light-Emitting Diodes (LEDs) which are powered by a power generating circuit within the spinning rotor. Other gyroscopic exercise balls are provided with a digital display and memory to display and store the speed of the rotor. These gyroscopic exercise balls can be plastic or metal, with increased weight of metal balls making the exercise more challenging by producing more torque.
The ability to calculate and display the speeds of the rotor have given users some indication of the relative intensity of their workout and allows users to compete against their own scores and the scores of others. However, the speed of the rotor does not provide an accurate representation of the intensity of the workout and can actually cause users to use improper and unsafe form to achieve higher speeds, thereby increasing susceptibility to injury, such as a torn muscle or ligament. Thus, knowledge of rotor speed is not sufficient to assess the impact of the exercise.
Therefore, what is needed is a gyroscopic exercise ball which provides a more accurate representation of the intensity of a workout and which allows for a better evaluation of the exercise.
To accurately assess the exercise quantitatively and determine whether the exercise is providing the proper therapeutic or strengthening benefit, it is useful to measure, inter alia, the forces applied by the user, the amount of calories expended, the range of motion and the degree to which the exercise is being performed to an optimal form. The gyroscopic exercise balls currently available do not provide such functionality, and consequently, there is no way to assess an individual's exercise.